<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script src="./js/vue.js"></script>
    <div id='app'>
       <div ref="self">test</div>
    </div>
    
    <script>
        let app =new Vue({//销毁实例用app.$destroy()函数
             el:"#app",
             data:{
                msg:'hello world'
             },
             beforeDestroy() {//实例被销毁之后获取不到页面中的div元素，因此实例被销毁以后无法通过vue实例操作dom元素
                console.log('销毁之前');
                console.log(this.$refs.self);
                console.log(this.msg);
                console.log(app);
             },
             destroyed() {
                console.log('销毁之后');
                console.log(this.$refs.self);
                console.log(this.msg);
                console.log(app);
             },
        })
    </script>
</body>
</html>